When should TAGs be preferred over BRANCHING and vice versa (in CVS)?

Question

I think title should be good enough.

Answer 1

Tags should be used when you want to mark a milestone. The milestone could be as small as a daily build.

Branches should be used when you want to make changes independently from another branch/trunk.

Answer 2

Branching should also be used for major milestones, such as a releases. This depends on your branching strategy though.

Answer 3

Tags

Think of it as a snapshot in time. I want to be able to go back to that exact point. However, it will never change. You do not do a checkin on a tagged element.

Things that can get tagged:

• Releases (major and minor)
• Patches sent to customers
• Bug fixes
• Milestones (alpha, beta, etc...)
• Successful Daily build

Branches

The branch will have development performed on it (i.e. checkins).
You might create a branch from a tag (to do a bug fix for example).
You might create a branch to develop a feature and then merge it back to the main trunk.
You might create a branch for a release (minor or major).

The key point is that branches could be modified, and tags should not be.

Answer 4

Apropos other replies,

We use tags for minor point releases and branches for releases. So for example,

v1.0 <-- Branch  
  v1.0.1 <-- Tag  
  v1.0.2 <-- Tag  
v1.1 <-- Branch  
  v1.1.1 <-- Tag  
  v1.1.2 <-- Tag  
v1.2 <-- Branch  
  v1.2.1 <-- Tag  
  v1.2.2 <-- Tag  
v1.3 <-- Branch  
  v1.3.1 <-- Tag  
  v1.3.2 <-- Tag  
v1.4 <-- Branch  
  v1.4.1 <-- Tag  
  v1.4.2 <-- Tag  
v1.5 <-- Branch  
  v1.5.1 <-- Tag  
  v1.5.2 <-- Tag

To use a Microsoft analogy, a Branch is a release of Windows (95, XP, Vista, etc) and a tag is a service pack.